1. Field of the Invention
The present invention relates to a cover for a cutting blade used in a brush cutter.
2. Description of the Related Art
Conventionally, a brush cutter has been used for works such as mowing or cutting of small branches. FIG. 6 shows an example of such a brush cutter. Referring to FIG. 6, a brush cutter 1 is provided with a three lobe cutting blade 3 at a tip end of a rod 14. The three lobe cutting blade 3 includes three blades radially extended from a base portion thereof. In the brush cutter 1, the cutting blade 3 is rotated by an engine (or motor) 2 to reap grasses, trees, and the like.
When work is completed or a work place is changed, it is necessary to transfer or carry the brush cutter 1. In this case, when the cutting blade 3 makes contact with very hard things such as rocks, a cutting portion of the blade 3 might be damaged. To avoid this, a cutting blade cover is generally attached to the cutting blade 3 when the brush cutter 1 is transferred or carried. For example, a cutting blade cover 4 shown in FIG. 7 is attached to the cutting blade 3.
Referring to FIG. 7, the cutting blade cover 4 comprises a circular base plate 5 and a push rod 6 rotatably attached to the base plate 5. The cutting blade cover 4 is attached to the cutting blade 3 according to the following procedure. First, the base plate 5 is brought into abutment with the cutting blade 3 from below of the cutting blade 3. In this state, then, the push rod 6 is rotated around a pivot 8 with respect to the base plate 5 and then engages with a hook 9 provided on the base plate 5. Thereby, the cutting blade 3 is sandwiched between the base plate 5 and the push rod 6 and the cutting blade cover 4 is attached to the cutting blade 3.
However, the following problems arise when the conventional cutting blade cover 4 is applied to the three lobe cutting blade 3.
The cutting blade three lobe shaped, while the base plate 5 of the cutting blade cover 4 is a circular flat plate. Therefore, with the cutting blade cover 4 attached to the cutting blade 3, the base portion 5 of the cutting blade cover 4 is only contact with a lower face of the cutting blade 3 and an outer periphery of the cutting blade 3 is exposed. Consequently, cutting portions of the cutting blade 3 are not sufficiently protected.
In addition, since the cutting blade 3 is pushed against the base plate 5 by means of the push rod 6 to be fixed to the base plate 5, play tends to occur and the cutting blade cover 4 is apt to be detached from the blade 3, which requires careful handling.
The present invention has been developed for the purpose of obviating the above-described problems and it is an object of the present invention to provide a cutting blade cover for a brush cutter that is capable of reliably protecting a three lobe cutting blade when the brush cutter is transferred or carried.
According to an aspect of the present invention, there is provided a cutting blade cover for a brush cutter for protecting a three lobe cutting blade including a base portion attached to a rotating shaft of the brush cutter, a first blade, a second blade, and a third blade, wherein the first, second and third blades are protruded radially from the base portion, comprising: a central portion having a central through hole; a first blade accommodating portion; a second blade accommodating portion; and a third blade accommodating portion, wherein the first, second, and third blade accommodating portions are provided radially from the central portion, a first concave portion is formed in the first blade accommodating portion and has an inner shape conforming to an outer shape of the first blade to cover an outer periphery of a cutting portion of the first blade, a second concave portion is formed in the second blade accommodating portion and has an inner shape conforming to an outer shape of the second blade to cover an outer periphery of a cutting portion of the second blade, a third concave portion is formed in the third blade accommodating portion and has an inner shape conforming to an outer shape of the third blade to cover an outer periphery of a cutting portion of the third blade, and the first blade accommodating portion includes a slit extending from an outer end thereof to the central through hole to widen the first concave portion.
With such a configuration, in order to laterally widen the first blade accommodating portion, a force is exerted to cause the slit to be opened, and the first concave portion can be thereby widened. In this state, the second blade and the third blade of the cutting blade are respectively fitted into the second concave portion and the third concave portion from a direction of the first concave portion. Then, the first blade of the cutting blade is inserted into the first concave portion and the force being exerted on the first blade accommodating portion is released to cause the slit to be closed, so that the first concave portion returns to its initial state. Thereby, the first blade is fitted into the first concave portion. Alternatively, the following procedure may be employed. First, the second blade and the third blade are respectively fitted into the second concave portion and third concave portion. Then, in order to laterally widen the first blade accommodating portion, the force is exerted to cause the slit to be opened and the first concave portion can be thereby widened. In this state, the first blade is fitted into the first concave portion. Then, the force being exerted on the first blade accommodating portion is released to cause the slit to be closed and the first concave portion returns to its initial state.
Since the first, second, and third concave portions have the inner shapes respectively conforming to the outer shapes of the first, second, and third blades, the respective blades can be fittingly covered by the respective concave portions. Further, the cutting blade cover is easily attachable/detachable to/from the cutting blade.
It is preferable that the first blade accommodating portion is provided with a pair of engagement portions protruded inwardly of the first concave portion from a side wall face of the first concave portion and apart from a bottom wall face of the first concave portion, for holding the first blade.
It is preferable that the first blade accommodating portion is provided with a pair of handles on both sides of outside of the first blade accommodating portion, for opening the slit, the slit being situated between the handles.
It is preferable that the central through hole has a cutout formed in an inner wall face of the central through hole at a position opposite to a position at which the slit communicates with the central through hole.
It is preferable that the second blade accommodating portion has a bag-shaped portion at an outer end of the second concave portion, for holding the second blade.
It is preferable that the central portion, the first blade accommodating portion, the second blade accommodating portion, and the third blade accommodating portion are made of resin and integrally formed by blow molding.
With such a configuration, the first, second, and third concave portions can be easily formed. In particular, the blow molding makes an outer peripheral face of the cutting blade cover for the brush cutter smooth and makes it possible to manufacture the cutting blade cover that is lightweight, superior in strength and impact resistance, and constituted by a single member at a low cost.
It is preferable that the central portion, the first blade accommodating portion, the second blade accommodating portion, and the third blade accommodating portion respectively have hollow portions inside thereof, the hollow portions communicating with one another.
These objects as well as other objects, features and advantages of the invention will become more apparent to those skilled in the art from the following description with reference to the accompanying drawings.